Robotic roller hemming alignment apparatus and method

ABSTRACT

A robotic roller hemming apparatus for hemming an upturned edge of an outer metal panel over a peripheral edge of an inner panel superimposed on the outer panel adjacent the upturned edge includes a hemming roller having a peripheral surface. The peripheral surface includes a hemming portion for pressing the upturned edge of the outer panel and a follower portion juxtaposed the hemming portion. The hemming apparatus also includes a robot hand and a lower die. The robot hand rotatably supports the hemming roller and controls the hemming roller in the direction of motion of the hemming. The lower die has a hemming surface for supporting the outer metal panel thereon and a two dimensional guide for guiding the hemming roller along two axes relative to the hemming motion, thereby maintaining axial positioning of the hemming roller independent of the robot hand.

TECHNICAL FIELD

The present invention relates to joining nested metal panels to form vehicle closure panels and more particularly to robotic roller hemming.

BACKGROUND OF THE INVENTION

A conventional robotic roller hemming apparatus, as shown in FIG. 1, includes an angular guide surface 10 machined or ground on the side of an anvil 12 or lower die to locate a hem roller 14, this guide surface controls the hemming roller in a single direction D1 only during the prehem step. Control of the location of the hemming roller along other axes is provided by the robot positioning control. Conventionally, the guide surface 10 is cut roughly at a 45 degree angle relative to the hemming die in the local region. It is desirable to control the robotic hemming roller 14 in at least two directions independent of the robotic positioning control.

SUMMARY OF THE INVENTION

The present invention provides a robotic hemming roller that maintains positioning in at least two directions independent of the robotic positioning control. Accordingly, the robotic hemming roller includes a follower for following a two dimensional guide on an edge of a hemming anvil or hemming die as the hemming roller prehems a standing flange on a panel of the assembly being hemmed.

More specifically, the robotic roller hemming apparatus for hemming an upturned edge of an outer metal panel over a peripheral edge of an inner panel superimposed on the outer panel adjacent the upturned edge includes a hemming roller having a peripheral surface including a hemming portion for pressing the upturned edge of the outer panel and a follower portion juxtaposed the hemming portion. The roller hemming apparatus also includes a robot hand rotatably supporting the hemming roller and controlling the hemming roller in the direction of motion of the hemming. A lower die having a hemming surface supports the outer metal panel thereon and includes a two dimensional guide for guiding the hemming roller along two axes relative to the hemming motion. The guide maintains axial positioning of the hemming roller independent of the robot hand.

In one embodiment, the hemming roller follower portion may be a V-shaped groove and the two dimensional guide may be a complementary wedge shaped section around an edge of the lower die. In another embodiment, the hemming roller follower portion may be a groove having an arcuate cross section and the two dimensional guide may be a complementary radius around an edge of the lower die, whereby the hemming roller can be rotated while maintaining directional stability in two directions independent of robotic positioning control.

These and other features and advantages of the invention will be more fully understood from the following detailed description of the invention taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side view of a prior art roller hemming apparatus performing a hemming operation;

FIG. 2 is a side view of a robotic roller hemming apparatus in accordance with the present invention performing a hemming operation;

FIG. 3 is a side view of a hemming roller of the robotic roller hemming apparatus of FIG. 2;

FIG. 4 is a side view of an alternative embodiment of a robotic roller hemming apparatus in accordance with the present invention; and

FIG. 5 is an enlarged side view of the robotic roller hemming apparatus of FIG. 4 illustrating an arcuate follower and complementary guide.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in detail, numeral 20 generally indicates a robotic roller hemming apparatus in accordance with the present invention. The robotic roller hemming apparatus 20 maintains positioning of a hemming roller in at least two directions independent of the robotic positioning control.

As shown in FIGS. 2 and 3, the robotic hemming roller apparatus 20 for hemming an upturned edge 22 of an outer metal panel 24 over a peripheral edge 26 of an inner panel 28 superimposed on the outer panel 24 adjacent the upturned edge 22 includes a hemming roller 30 having a peripheral surface 32 including a hemming portion 34 for pressing the upturned edge 22 of the outer panel 24 and a follower portion 36 juxtaposed the hemming portion 34. The roller hemming apparatus 20 further includes a robot hand 38 rotatably supporting the hemming roller 30 and controlling the hemming roller 30 in the direction of motion of the hemming. The roller hemming apparatus 20 also includes a lower die 40 having a hemming surface 42 for supporting the outer metal panel 24 thereon and a two dimensional guide 44 for guiding the hemming roller 30 along two axes A1, A2 relative to the hemming motion.

In one embodiment, as shown in FIGS. 2 and 3, the hemming roller follower portion 36 may be a V-shaped groove and the two dimensional guide 44 may be an edge 46 having a complementary wedge shaped section around the lower die 40. This guide 44 and follower 36 arrangement provides control of the hemming roller 30 along axes A1, A2 relative to the hemming motion that are perpendicular to the two flat surfaces 48, 50 of the edge 46. The flat surface 48 provides control in the A1 direction and the flat surface 50 provides control in the A2 direction, thereby axially stabilizing the hemming roller 30. Flat surfaces 48, 50 also provide superior directional stability of the hemming roller 30 for prehemming operations where maintaining a prehem angle is important.

FIGS. 4 and 5 illustrate an alternative embodiment of the robotic roller hemming apparatus 120. In apparatus 120, the hemming roller follower portion 136 is a groove 137 having an arcuate cross section. The two dimensional guide 144 is a complementary radius 145 around extending edge 146 of the lower die 140. In this embodiment, the hemming roller 130 can be rotated around the radius 145 by rotating the hemming roller in a plane extending through the hemming roller axis. Directional stability in the two directions A1, A2 is maintained independent of the robotic positioning control. This guide 144 and follower 136 arrangement provides the same non-robotic directional control in the A1, A2 directions without the planar features 48, 50 of the first described embodiment. The combination of the groove 137 and radius 145 provides a line around the hemming die 140 about which the hemming roller axis H can be rotated allowing for prehemming of the hemming roller around a hem flange on lower die 140 while maintaining axial stability of the hemming roller 130.

Although the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims. 

1. Robotic roller hemming apparatus for hemming an upturned edge of an outer metal panel over a peripheral edge of an inner panel superimposed on the outer panel adjacent the upturned edge, the roller hemming apparatus comprising: a hemming roller having a peripheral surface including a hemming portion for pressing the upturned edge of the outer panel and a follower portion juxtaposed said hemming portion; a robot hand rotatably supporting said hemming roller and controlling the hemming roller in the direction of motion of the hemming; and a lower die having a hemming surface for supporting the outer metal panel thereon and a two dimensional guide for guiding said hemming roller along two axes relative to the hemming motion, thereby maintaining axial positioning of the hemming roller independent of the robot hand.
 2. Robotic roller hemming apparatus as in claim 1 wherein said hemming roller follower portion is a V-shaped groove and said two dimensional guide is an edge having a complementary wedge shaped section around said lower die.
 3. Robotic roller hemming apparatus as in claim 1 wherein said hemming roller follower portion is a groove having an arcuate cross section and said two dimensional guide is a complementary radius around an edge of said lower die, whereby said hemming roller can be rotated while maintaining directional stability in two directions independent of robotic positioning control.
 4. A method for roller hemming an upturned edge of an outer metal panel over a peripheral edge of an inner panel superimposed on the outer panel adjacent the upturned edge, the method comprising the steps of: providing a hemming roller having a peripheral surface including a hemming portion for pressing the upturned edge of the outer panel and a follower portion juxtaposed said hemming portion; providing a robot hand rotatably supporting said hemming roller and controlling the hemming roller in the direction of motion of the hemming; and providing a lower die having a hemming surface for supporting the outer metal panel thereon and a two dimensional guide for guiding said hemming roller along two axes relative to the hemming motion, thereby maintaining axial positioning of the hemming roller independent of the robot hand. 